The generation and control of relativistic charged-particle beams operating at high frequencies is of import to a variety of different applications. A few example applications range from experimental physics, imaging, detection and even medical treatment. Many current sources of such relativistic charged-particle beams require a long path (e.g., hundreds or thousands of meters) over which to generate and control the relativistic charged-particle beams. This type of requirement, however, frustrates the use of relativistic charged-particle beams in many applications. One example of an application that would benefit from a smaller and controllable relativistic charged-particle beam source is in the field of security screening.
Prevention of radiological terrorism is of growing concern. The demand for nuclear detectors at border crossing and shipping locations is ever increasing. The sheer quantity of goods that enter the United States (over 7 million cargo containers enter U.S. ports each year), however, renders many current detection mechanisms inadequate or impractical. Moreover, the nuclear detectors that require significant training and expertise render the systems difficult to use by law enforcement officials. For example, active nuclear detector systems emit gamma rays to identify nuclear materials in containers. Many of these nuclear detectors are prohibitively expensive, difficult to operate and easily fooled by adequate shielding.
As a possible improvement for such nuclear detectors, as well as for many other applications, development efforts for ultra-low emittance and optically bunched electron sources as well as for dielectric-structure laser-driven particle accelerators are of great import.
While the invention is amenable to various modifications and alternative forms, specifics thereof have been shown by way of example in the drawings and will be described in detail. It should be understood, however, that the intention is not to limit the invention to the particular embodiments described. On the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.